Multiple-expansion piston steam engine



April 23, 1940. w. RIEGER MULTIPLE-EXPANSION PISTON STEAM ENGINE Filed Feb. 26, 1937 I 1. .il

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Patented Apr. 23, 1940 2,198,552

UNITED s'rrss rTENT OFFICE MULTIPLE-EXPANSION PISTON STEAM ENGINE Willi Rieger, Kassel-Wilhelmshohe, Germany Application February 26, 1937, Serial No. 128,005' In Germany March 3, 1936 3 Claims. (01. 121-102) This invention relates to a multiple-expansion a diameter of 970 mm. which is, however, so large Piston steam engine provided with a speedthat it is practically out of the question to build change gearing between the crank shaft of the such an engine. But if, according to this inhigh-pressure stage and a crank shaft of a lower vention, 800 revolutions per minute are used in 5 stage. With a known engine of this type a spurthe low-pressure stage, the diameter of the low- 5 wheel gearing is inserted between two crank pressure cylinder will amount to only 485 mm. shafts lying side by side. In contradistinction which is a very acceptable size for this cylinder. thereto the crank shafts are, in the present in- In the modification shown in Fig. 3 all three vention, arranged in a line and are connected crank shafts rotate with different speeds of with one another by planet-gearings having a revolution. Between the shaftB of the high- 19 corresponding ratio, whereby it is rendered pospressure stage and the shaft'9 of the mediumsible to arrange the engine upon a frame of the pressure stage is inserted the planet-Wheel gearusual construction. iii, and between said shaft 9 and the shaft The invention is illustrated diagrammatically ii of the low-pressure stage is inserted the and by way of example on the accompanying planet-wheel gearing 3. The low-pressure stage'l drawing on which is shown aconstructional form is divided into two low-pressure cylinders 3, 3. of an engine designed according to this invention It is assumed that the planet-wheel gearings l0, and on which Figure 1 is a front View of the i3 have a ratio of 1:1.5: 2. With a number of engine, the change-speed gearing and the shaft revolutions of 300 in the high-pressure stage is 20 bearings being, however, drawn in axial section. obtained in the'medium-pressure stage a number 2 Figure 2 is a vertical transverse section through of revolutions of 450 and in the low-pressure this engine in the line II-II of Fig. 1, and Figstage a number of revolutions of 600. In accordure 3 is a representation similar to Fig. 1, but ance therewith, the diameter of the high-presprovided with two change-speed gearings, these sure cylinder being supposed to 'be 100 mm., the

latter and the shaft-bearings being again drawn diameter of the medium cylinder will be 155 mm. 25

in axial section. and the diameter of each of the low-pressure Referring to the figures, i denotes the highcylinders will be 390 mm. pressure cylinder, 2 the medium-pressure cylin- The work done may be drawn from the highder, and 3 the low-pressure cylinder. I have pressure side of the engine or from the low-presabstained from entering into details of the engine sure side of the same, just as requisite in a given as it is of a known design. case. In Fig. 1 one half of a coupling M is se- In Fig. 1 the crank shaft 4 of the high-pressure cured to the high-pressure shaft 4 and in Fig. 3

stage and the crank shaft 5 of the medium-presone half of a coupling I5 is afiixed to the lowsure stage are rigidly connected with one another pressure shaft E2 of the engine.

so that they rotate with the same speed. Be- I claim:

tween the crank shafts 4 and 5 on the one hand i. A reciprocating steam engine having a pluand the crank shaft 6 of the low-pressure stage rality of expansion stages comprising a plurality on the other hand is inserted a planet-wheel of linearly ali d c h s ch be n Comgearing I of th un type hi h lik i d mon to atleast one stage and different from a he t be dgscribed in t l as t is of a known crankshaft common to at least oneother stage. sign. The ratio of the gear depends upon the and a $1131 p planetary gear ssi n Syssize f t cogwheels of t Same tem connecting at least one of said crankshafts Supposing, the ratio of gearing amount to 1A, to an adjacent linearly aligned crankshaft for so that the crank haft 5 of the lowmressure permitting the crankshafts of the various stages 5 stage makes 800 revolutions per minute if the to rotate at m ream/6 P I number of revolutions of the shafts (i and 5 A Steam engme as clalm warmgs on amounts to 200 per minute, and supposing fub said crankshafts, a bearing supporting frame ther that the ratio of expansion between the having lmearly engined bearmgs thereon, Said three cylinders be 1:3.7:60. With the usual conframe Supportmg Sa1d crafnkshaflfts and P s 0 struction of engines of the type in question,

team engme as m 61mm Said Stages in which the three crank shafts rotate with the Comprlslng a high-pressure, a -p s re, same speed, viz. 200 in the above example, the and a "p es ur S e, a cr nkshaft for each' medium-pressure cylinder would have to be destage, and a planetary gearing connecting each signed with a diameter of 240 mm. and the lowtwo adjacent crankshafts.

5 pressure cylinder would have to be designed with WILLI RIEGER. u 

